Drilling machine with tapping attachment



7, 1939. H. w. BOCKHOFF ET AL 6,

DRILLING MACHINE WITH TAPPING ATTACHMENT Filed Nov. 6, 1937 3 Sheets-Sheet 2 Oct. 17, 1939. H. w. BOCKHOFF ET! AL 2,176,414

DRILLING MACHINE WITH TAPPING ATTACHMENT Filed Nov. 6, 1937 3 Sheets-Sheet 3 wwww. PM Eh W norm '20 the taps into the work.

Patented Oct. 17, 1939 UNITED STATES PATENT OFFICE DRILLING MACHINE WITH TAPPIN G ATTACHMENT Indiana Application November 6, 1937, Serial No. 173,069

11 Claims.

Our invention relates generally to machine tools, and more particularly to an improved tap ping mechanism for hydraulically controlled drilling machines.

It is generally not feasible to use a machine tool having a hydraulically traversed head of usual construction for tapping operations, because of the possibility that due to slight variations in the rate of feed, the taps may become jammed and broken. It is therefore an object of our invention to providea machine tool having a hydraulically operated drilling head with improved means whereby the tool may be utilized for performing tapping operations.

A further object is to provide an improved tapping attachment for hydraulically actuated drill heads of machine tools whereby the head and the hydraulic actuating mechanism may be disengaged and the head advanced by .hand to feed Other objects will appear from the following description, reference being had tothe accompanying drawings, in which;

Fig. 1 is a side elevation of a machine tool 85 having a hydraulically actuated'drilling head,

and incorporating our improved hand feed tapping mechanism;

Fig. 2 is a partially diagrammatic sectional view showing the control and feed means for the hand 80 tapping mechanism;

Fig. 3 is a front elevational view of the drill head, a portion of the casing of the head being broken away and parts removed to show the parts of the hand feed tapping mechanism; 35 Fig. 4 is a fragmentary sectional view taken on the line 44 of Fig. 3; Figure 5 is a side elevation showing the opposite side of the embodiment illustrated in Figure 1; and

Figure '6 is a diagrammatical illustration of the electrical circuits which comprise the electrical means for controlling the hydraulically operated means of the invention.

Referring to Fig. 1, the machine tool comprises a base lll to which is secured a column l2. A neck I4 is secured at the top of the column l2 and carries a motor 16. The front of the column has ways I8 for a vertically reciprocable head 20, the latter being raised and lowered by hydraulic means and being automatically controlled in the well-known manner. vided with a cluster box 22 from which a plurality of spindles 24 project, the spindles being illustrated as carrying taps 26. The taps are preferably connected to the spindles by floating The head is pro-' connections which permit limited longitudinal movement of the taps with respect to their spindles.

As best shown in Figs. 2 and 4, the head 20 is adapted to be raised and lowered by a piston 5 rod 28 which is reciprocable in a hydraulic cylinder 30 secured to the column l2 of the machine. A detachable interlocking connection between the piston rod 28 and the head 20 is provided by means of a shot bolt 32 which is slidable in a bore 34 formed in a suitable part of the casting of the head 20 and has a bifurcated end 36 which is adapted to engage about a reduced diameter portion 38 of the pistonrod 28. The piston rod 28 is provided with a suitable shoulder 40 adapted to abut against a machined surface 42 formed on the casting 20 and to be locked thereagainst by the shot bolt 32 when the latter is projected to the rear (to the left Fig. 4). To assure that the shot bolt will lock the casting of the head 20 securely against the shoulder, the bore 34 is at an angle of approximately 5 relative to the horizontal, and thus the shot bolt may wedge itself firmly around the reduced portion 38 of the piston rod and securely lock the head 20 to the piston rod.

The shot bolt 32 is actuated'by means of a pinion 44 keyed to a shaft 46 which is suitably journaled in the head 20 and at its right hand end (Fig. 22) carries a helical gear 48. The helical gear 48 meshes with a complementary pinion 50 secured to a shaft 52. The outer end of the shaft 52 is provided with a screw threaded portion 54 engaging an internally threaded bushing 56 which is secured against rotation by one or more cap screws 58. A lock nut 60 is secured to the end of v the threaded portion 54, being held in position by a set screw 62. A shaft 64 is keyed to the shaft 52 and extends through a tubular shaft 66 A handle 68 is secured to the outer end of the shaft 64. A clutch member 10 is secured to the tubular shaft 66 and is cooperable with a complementary member 16 formed on a bevel gear 18. The bevel gear 18 is provided with a hub 80, and is freely rotatable in its bearing and with respect to the tubular shaft 66. A handwheel 84 is non-rotatably secured to the end of the tubular shaft 66 by means of a key 86 and is locked in position by means of a set screw 88. A compression coil spring 90 engages a collar 92 secured to the tubular shaft 66 and normally 50 urges the tubular shaft 66 rearwardly to cause disengagement of the clutch members 10 and 76.

The bevel gear 16 meshes. with a bevel pinion 93 keyed to the end of a shaft 94, to the other end of which a spur gear 96 isv keyed. The spur 55 The shaft 46 has a reduced diameter extension I which at its end carries a cam I02. The cam I02 is engageable with the end of a plunger I04 which actuates a limit switch I06.

An adjustable stop I08 carried by a projection I I0 fixed with respect to the column I2, is provided to limit downward movement of the piston rod 28, the stop I08 being adapted to be locked in adjusted position by means of a suitable lock nut 2'.

Referring now to Figs. 5 and 6 for a consideration of the electrical means employed to control and operate the machine tool in its several uses, the electrical units of the several circuits comprise the forward winding I08 and the reverse {winding IIO of the motor I6; a normally open Start contact switch II2; a normally closed "Stop contact II4; two normally open contact switches, H6 and H8 for the rapid forward traverse solenoid I and for the rapid reverse solenoid I22, respectively, which in turn operate in a well known manner a valve (not shown) which controls the hydraulic movement of the piston 28; a four pole double contact tap limit switch I24; a four pole double contact switch I 26 carried by the column I2, see Fig. 5, and actuated by the cam I21 on the head 20 when the head is at an upper limit; the reverse relay I28 controlling a normally open switch I 28a. and a normally closed switch I28b, also the switch I28c which when closed, completes a circuit through the reverse winding IIO between the power lines I30 and I3I; a forward relay I32 which controls two normally open switches I32a and I320, the latter completing, when closed, a circuit through the forward winding I08 of the motor; and], the limit switch I06 already referred to which comprises a four pole double contact construction controlled by the camt I02.

In using the machine tool in a drilling operation, the handle 68 is turned clockwise, (Fig. 3), thus causing the screw portion 54, (Fig. 2), of the shaft 52 to feed into the bushing 58 substantially to the position in which it is shown in Fig. 2. During this rotation of the shaft 52, the helical pinion drives the helical gear 48 and hence rotates the shaft 46 in a clockwise (Fig. 4) direction to move the shot bolt 32 into locking engagement with the piston rod 28. If the head 20 does not happen to be in exactly the correct position with respect to the piston rod 28, the shot bolt will wedge the head upwardly to such position to cause engagement of its surface 42 against the shoulder 40 of the piston rod. Under these circumstances, the movement of the handle 68 as described has moved the cam I02 to permit the contact I 01 of the switch I06 to close the poles of IBM. With the parts in this position, the machine may be used to perform drilling operations in the usual manner, utilizing the customary automatic electro-hydraulic controls and operating means for the rapid traverse, feed, reverse feed, and reverse rapid traverse, as follows:

With the poles I 06a closed, the start switch I I2 is pressed, the under voltage relay I34 is energized thereby and establishes a holding circuit in a well known manner through the switch I34a to furnish power to the line I36. The closure of the poles I24a of the limit switch when the head 20 is raised, energizes from the line I36 the forward relay I32 through the normally closed switch I28b. Switch I32a closes, thereby creating a holding circuit which includes the limit switch I06a gear 88 meshes with a rackfl which is fixed to the column I2 of the machine.

and the normally closed switch I282). The forward relay I32 also closes the power contactor I32b to start the motor I6 forward by energizing the forward winding I08. Thereafter, the motor will run forward continuously.

The forward traverse switch H8 is now closed and this energizes the rapid forward traverse solenoid I20 through the cam closed switch |28a and the manually set switch I06a. Thereafter, the head completes one drilling cycle automatically in which a feed traverse and a rapid return is accomplished, it being appreciated that the traverse of the head may be reversed at any time during the cycle by closing the reverse switch II8 which energizes the rapid reverse solenoid I22.

When, however, it is desired to use the machine to perform tapping operations, the head may be actuated hydraulically for the rapid forward or downward traverse to bring the taps into position adjacent the work, the control dogs being set so that the head will discontinue its downward movement just prior to the engagement of the taps with the work, with the end of the piston rod 28 abutting against the adjustable stop I08. After the head has stopped in this position, the operator will swing the handle 68 counter-clockwise, (Fig. 3), whereupon the shaft 52 will be rotated, and, due to its threaded part 54, will move longitudinally until the nut engages the face of the bushing 56, against which it looks. During.

this rotary movement of the shaft 52, the helical pinion 50 carried thereby will rotate the helical gear 48 and hence the shaft 46 and pinion 44 counter-clockwise, thus withdrawing'the shot bolt 32 from the groove in the piston rod 28 around the reduced diameter portion 38 thereof and operating the limit switch I06 to break the switch I08a and render the control for the hydraulic traverse inoperative and to close the switch I06!) to make ready the circuit for automatically reversing the motor I6. When the shot bolt 32 is thus withdrawn, the head 20 may be freely traversed by hand while the piston rod 28 remains stationary.

The forward movement of the shaft 52 caused by the counter-clockwise movement of the handle 68 thereafter causes the engagement of the clutch member 10 with its complementary member I6, whereupon a driving connection between the tubular shaft 68 and the bevel gear 18 is established. Thereafter, the head may be traversed downwardly to feed the taps into the work by rotating the hand-wheel 84.

The latter will, through the tubular shaft 66, bevel gears I8, and 93, shaft 94, the spur gear 96, cause the head to move downwardly with respect to the fixed rack 98. By observing the rate of feed of the taps 28 into the work, the operator may bring the head down at the required tapping speed. As previously stated, the tapping tools are preferably connected to their respective spindles by a suitable connection which permits an appreciable amount of longitudinal movement of the taps with respect to their spindles. Because of this type of connection of the taps with the spindles, the operator is permitted a considerable latitude with respect to the rate at which the head may be advanced and retracted. After the holes in the work have been tapped to a sufiicient depth, the direction of rotation of the taps may be reversed and the head raised manually in accordance with the rate at which the taps feed out of the work. Reversal of the taps is accomplished by automatically reversing in a well-known manner the contact of the means during the operations of i'eeding and withtap switch I24 when the predetermined depth is reached.

With the reversal oi the tap limit switch, the contact and poles I24b complete a circuit through the reverse relay I 28 which when energized breaks the relay switch I26b to drop, out the forward relay I32 and to close the contact switch I260 to furnish power to the reverse winding III! of the motor. A holding circuit for the reverse relay is established when its relay switch I280 closes. This reverses the direction of rotation of the taps for withdrawal and after the taps clear their cuts the tap limit switch I24 returns to its starting position. The reverse winding III] of the motor I6 is held in by the holding circuit I28a. This holding circuit is dropped out when the handle at is turned clockwise to engage the shotbolt and operates switch I 66. When switch I06 7 is operated, contact I06b is opened and this breaks the holding circuit oi I2 and closes contact I28b. Then, with tap limit switch I24 at its starting, the closing of the contact I26b energizes the forward relay I32 to start the forward tuming of the taps for the next cycle.

After the direction of rotation 01' the taps has been reversed and they have been drawn from the work and the head returned to the position at which the tapping operation was started, the operator will swing the handle 68 clockwise, thereby disengaging the clutch part 10 from the clutch part I6 and reengaging the shot bolt 32 in the groove surrounding the reduced" diameter portion 38 of the piston rod 28. At the same time, the cam I02 will actuate the limit switch I66 to recondition the machine for initiation of automatic control and cause the rapid reverse, (upward), traverse of the head so as to clear the taps sufllciently from the work to permit removal of the latter from the machine.

If desired, the rapid traverse operations 01' the head to and from the work, as well as the forward and reverse feed traverse operations, may be performed manually, in which event, the clutch I6, III will be kept engaged and the shot bolt 32 disengaged. When the machine is operated in this manner, the automatic controls will be utilized only for the purpose oi automatically reversing the spindle driving motor at the ends of its stroke.

Although the invention has been illustrated and described as applied to a vertical column type 01 machine, it may be utilized in a horizontal type with equal advantage.

While we have shown and described a particular embodiment of our invention, it will be readily understood by those skilled in the art that variations may be made in the construction disclosed without departing from the basic features of our invention. We therefore do not wish to be limited to the precise construction disclosed, but wish to include within the scope of the invention all such modifications and variations which will readily suggest themselves.

What we claim as new and desire to secure by United States Letters Patent is:

1. In a. machine tool, the combination of a head having a plurality of rotatable spindles carrying taps, automatically controlled hydraulic means for traversing said spindles toward and away from the work, hand operated means to traverse said head by hand for slow feeding movement thereof, and manually operated means to disconnect said head from said hydraulic traversing means and to condition said hand operated means for moving said head tree of said hydraulic drawing taps from the work.

2. In an automatic drilling and tapping machine, the combination of a tool carrying head, automatic means for rapidly traversing said head toward and away from the work, manually operated means for feeding said head into and out of the work during tapping operations, and manually operable mechanically connecting and disconnecting means for simultaneously rendering said automatic means inoperative and rendering said manually operated means operative.

' 3. In a machine of the class described, the combination oi a head, automatic means for moving said head toward and away from the work to be machined, manually operated means for moving the head slowly toward and away from the work, and means for disengaging said autcmatically operated means and engaging said manually operated means to permit hand feeding oi. the head toward and away from the work free of said automatic means.

4. In a machine tool, the combination of a column, a head reciprocable on said column, hydraulic means for traversing said head, manually operable means for traversing said head, and manually operable mechanically connecting and disconnecting means for simultaneously disengaging said hydraulic means from said head and rendering said manually operable traversing means operative.

5. In-a machine tool, the combination 01 ways, a head guided for movement on said ways and carrying a plurality of rotatable spindles, a rack fixed with respect to said ways, a pinion carried by said head and engaging said rack, a hand wheel, a driving connection between said hand wheel and said pinion, said driving connection including a clutch, hydraulically operated means for traversing said head on said ways, said last named means including a. piston rod having a groove formed therein, a shot bolt carried by said head and engageable in said groove to lock said head to said piston rod, and a single manually operable element for causing engagement and disengagement of said clutch and disengagement and engagement of said shot bolt with said piston rod. l"

6. In a machine tool, the combination 01' a body having ways, a head reciprocable on said ways, a plurality of rotatable spindles mounted in said head, hydraulic means for actuating said head, said hydraulic means including a cylinder and a piston rod, means for mechanically interlocking and disconnecting one of said last named elements with said head, manually operated means for actuating said interlocking means, and manually operable means for traversing said head on said ways.

'7. In a machine tool, the combination of a body having ways, ahead reciprocable on said ways, a spindle carried by said head, means to rotate said spindle, hydraulically operated means for traversing said head relative to said ways, a separable connection between said hydraulically operated means and said head, manually operable means for traversing said head relative to said ways, and a single manually operable control element for alternatively rendering said manually operated traversing means in operable and disengaging said separable connection.

8. In a machine tool, the combination of a body having ways, a head reciprocable on said ways, a plurality oi rotatable spindles carried by said head, hydraulically operated means for traversing said head relative to said ways, electrical means for controlling said hydraulically operated means, said electrical means including a limit switch, a separable connection between said hydraulically operated means and said head, manually operated means for traversing said head relative to said ways, and a manually opermechanically connecting and disconnecting means for rendering said automatic means inoperative and engaging said manually operated means to permit manual feeding of the head toward and away from the work, whereby tapping operations may be eifected.

10. In a machine tool, the combination of a body having ways, a head reciprocable on said ways, hydraulic means for actuating said head, including a cylinder and a piston rod, means for quickly interlocking and disconnecting one of said last named elements with said head, manually operated means for actuating said interlocking means, and manually operable means normally operative for traversing said head on said ways only when said head is disconnected.

11. In a machine tool, the combination of a body having ways, a head reciprocable on said ways, hydraulically operated means for traversing said head upon said ways, a shot bolt for interlocking said hydraulically operated means and said head, manually operable means for traversing said head relative to said ways, said last named means including a clutch and a single manually operable control element for operating said clutch to render said manually operated traversing means operable and for moving said shot bolt to non-interlocking position.

HARRY W. BOCKHOFF. RALPH RODAL. 

